package com.allsofts.pattern.course.proxy.dynamic.customer;

import java.io.*;

public class GPClassLoader extends ClassLoader{
    private File classPathFile;
    public GPClassLoader(){
        String classPath = this.getClass().getResource("").getPath();
        this.classPathFile = new File(classPath);
    }

    @Override
    protected Class<?> findClass(String name) throws ClassNotFoundException {
        String className = GPClassLoader.class.getPackage().getName()+"."+name;

        if (classPathFile != null){
            File classFile = new File(classPathFile,name.replaceAll("\\.","/")+".class");
            if (classFile.exists()){
                FileInputStream in = null;
                ByteArrayOutputStream out = null;
                try {
                    in = new FileInputStream(classFile);
                    out = new ByteArrayOutputStream();
                    byte [] buff = new byte[1024];
                    int len;
                    while ((len =in.read(buff))!=-1 ){
                        out.write(buff,0,len);
                    }
                    return defineClass(className,out.toByteArray(),0,out.size());
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }finally {
                    if (null != in){
                        try {
                            in.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                    if (null != out){
                        try {
                            out.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }
        }
        return null;
    }
}
